This week, members of the press and the public are up in arms over what they see as a possible violation of First Amendment rights. The Department of Justice investigated phone and email records of Fox News reporter James Rosen, who published information leaked by a government employee. The Justice Department is pursuing the leak under the Espionage Act, a law that dates back to World War I and was used to stop national defense secrets getting into enemy hands.

But more recently, the government has used the Espionage Act to pursue whistle-blowers and federal employees who leak classified information to the press. And all this buzz made us wonder, what exactly is this old law?

To help fill us in, we have Benjamin Wittes with us. He's a senior fellow in governance studies at the Brookings Institution. Benjamin Wittes, welcome to the program.

BENJAMIN WITTES: Thanks for having me.

LYDEN: What was the original intent of the Espionage Act?

WITTES: Well, the Espionage Act is a World War I era statute that prevents people from giving national defense information to foreign governments, but also to people domestically who are not authorized to have it. It not only forbids the original transmission by the authorized person to the unauthorized person, but that it also purports to forbid secondary transmissions by unauthorized people to each other.

So to give you an example of that, if somebody leaks information to NPR and NPR then turns around and publishes that information or broadcasts it on the radio, NPR itself may be in violation of it.

LYDEN: Let's turn back to the news at the moment, the Department of Justice using the Espionage Act investigation to go through the phone and email records of a reporter. In the case of Fox News' James Rosen, we should clearly state that he's not being prosecuted by this act, but the Department of Justice knows there was a leak to him. So as part of this investigation, they're trying to find out the sources of the leak. Why is this particular case getting so much attention?

WITTES: What from a journalistic point of view looks like pretty normal journalistic activity could be considered aiding and abetting a violation of the Espionage Act, and therefore a crime in and of itself. The aiding and abetting was things he did to facilitate the leak itself.

LYDEN: You know, the act is really old and was intended for wartime use originally. What are some other problems with its use today?

WITTES: Broadly speaking, the problems with the Espionage Act are that it is hopelessly broad. And we tend to use the Espionage Act - we think about the Espionage Act as forbidding disclosures of classified information. That's not really what the statute says. What the statute talks about is information related to the national defense. And so, you know, I think if you were to go take pictures of ships at Pearl Harbor, that is not classified information, but it arguably is information related to the national defense.

On the other hand, if you imagine a highly classified diplomatic cable that's sensitive for reasons having nothing to do with national defense, it's classified for other reasons. And so I think you do have this weird mismatch under the Espionage Act. The categories don't really line up very well with the modern classification system.

LYDEN: Do you think that this is going to be resolved in front of a court or in the court of opinion between journalists and the administration?

WITTES: Well, I think it's going to be resolved through a combination of pushback by the public and the press. But ultimately, Congress needs to resolve this issue. If we're going to have leak prosecutions, it's kind of crazy to have them on the basis of a statute that's nearly 100 years old and that is in all the ways we talk about not statute that really describes our modern reality very well.

LYDEN: Benjamin Wittes of the Brookings Institute, thank you so much for being with us.